drivers/gpu/drm/ttm/ttm_execbuf_util.c

   1 /**************************************************************************
   2  *
   3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 #include <drm/ttm/ttm_execbuf_util.h>
  29 #include <drm/ttm/ttm_bo_driver.h>
  30 #include <drm/ttm/ttm_placement.h>
  31 #include <linux/wait.h>
  32 #include <linux/sched.h>
  33 #include <linux/module.h>
  34
  35 static void ttm_eu_backoff_reservation_locked(struct list_head *list)
  36 {
  37         struct ttm_validate_buffer *entry;
  38
  39         list_for_each_entry(entry, list, head) {
  40                 struct ttm_buffer_object *bo = entry->bo;
  41                 if (!entry->reserved)
  42                         continue;
  43
  44                 if (entry->removed) {
  45                         ttm_bo_add_to_lru(bo);
  46                         entry->removed = false;
  47
  48                 }
  49                 entry->reserved = false;
  50                 atomic_set(&bo->reserved, 0);
  51                 wake_up_all(&bo->event_queue);
  52         }
  53 }
  54
  55 static void ttm_eu_del_from_lru_locked(struct list_head *list)
  56 {
  57         struct ttm_validate_buffer *entry;
  58
  59         list_for_each_entry(entry, list, head) {
  60                 struct ttm_buffer_object *bo = entry->bo;
  61                 if (!entry->reserved)
  62                         continue;
  63
  64                 if (!entry->removed) {
  65                         entry->put_count = ttm_bo_del_from_lru(bo);
  66                         entry->removed = true;
  67                 }
  68         }
  69 }
  70
  71 static void ttm_eu_list_ref_sub(struct list_head *list)
  72 {
  73         struct ttm_validate_buffer *entry;
  74
  75         list_for_each_entry(entry, list, head) {
  76                 struct ttm_buffer_object *bo = entry->bo;
  77
  78                 if (entry->put_count) {
  79                         ttm_bo_list_ref_sub(bo, entry->put_count, true);
  80                         entry->put_count = 0;
  81                 }
  82         }
  83 }
  84
  85 void ttm_eu_backoff_reservation(struct list_head *list)
  86 {
  87         struct ttm_validate_buffer *entry;
  88         struct ttm_bo_global *glob;
  89
  90         if (list_empty(list))
  91                 return;
  92
  93         entry = list_first_entry(list, struct ttm_validate_buffer, head);
  94         glob = entry->bo->glob;
  95         spin_lock(&glob->lru_lock);
  96         ttm_eu_backoff_reservation_locked(list);
  97         spin_unlock(&glob->lru_lock);
  98 }
  99 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
 100
 101 /*
 102  * Reserve buffers for validation.
 103  *
 104  * If a buffer in the list is marked for CPU access, we back off and
 105  * wait for that buffer to become free for GPU access.
 106  *
 107  * If a buffer is reserved for another validation, the validator with
 108  * the highest validation sequence backs off and waits for that buffer
 109  * to become unreserved. This prevents deadlocks when validating multiple
 110  * buffers in different orders.
 111  */
 112
 113 int ttm_eu_reserve_buffers(struct list_head *list)
 114 {
 115         struct ttm_bo_global *glob;
 116         struct ttm_validate_buffer *entry;
 117         int ret;
 118         uint32_t val_seq;
 119
 120         if (list_empty(list))
 121                 return 0;
 122
 123         list_for_each_entry(entry, list, head) {
 124                 entry->reserved = false;
 125                 entry->put_count = 0;
 126                 entry->removed = false;
 127         }
 128
 129         entry = list_first_entry(list, struct ttm_validate_buffer, head);
 130         glob = entry->bo->glob;
 131
 132         spin_lock(&glob->lru_lock);
 133         val_seq = entry->bo->bdev->val_seq++;
 134
 135 retry:
 136         list_for_each_entry(entry, list, head) {
 137                 struct ttm_buffer_object *bo = entry->bo;
 138
 139                 /* already slowpath reserved? */
 140                 if (entry->reserved)
 141                         continue;
 142
 143                 ret = ttm_bo_reserve_nolru(bo, true, true, true, val_seq);
 144                 switch (ret) {
 145                 case 0:
 146                         break;
 147                 case -EBUSY:
 148                         ttm_eu_del_from_lru_locked(list);
 149                         spin_unlock(&glob->lru_lock);
 150                         ret = ttm_bo_reserve_nolru(bo, true, false,
 151                                                    true, val_seq);
 152                         spin_lock(&glob->lru_lock);
 153                         if (!ret)
 154                                 break;
 155
 156                         if (unlikely(ret != -EAGAIN))
 157                                 goto err;
 158
 159                         /* fallthrough */
 160                 case -EAGAIN:
 161                         ttm_eu_backoff_reservation_locked(list);
 162
 163                         /*
 164                          * temporarily increase sequence number every retry,
 165                          * to prevent us from seeing our old reservation
 166                          * sequence when someone else reserved the buffer,
 167                          * but hasn't updated the seq_valid/seqno members yet.
 168                          */
 169                         val_seq = entry->bo->bdev->val_seq++;
 170
 171                         spin_unlock(&glob->lru_lock);
 172                         ttm_eu_list_ref_sub(list);
 173                         ret = ttm_bo_reserve_slowpath_nolru(bo, true, val_seq);
 174                         if (unlikely(ret != 0))
 175                                 return ret;
 176                         spin_lock(&glob->lru_lock);
 177                         entry->reserved = true;
 178                         if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
 179                                 ret = -EBUSY;
 180                                 goto err;
 181                         }
 182                         goto retry;
 183                 default:
 184                         goto err;
 185                 }
 186
 187                 entry->reserved = true;
 188                 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
 189                         ret = -EBUSY;
 190                         goto err;
 191                 }
 192         }
 193
 194         ttm_eu_del_from_lru_locked(list);
 195         spin_unlock(&glob->lru_lock);
 196         ttm_eu_list_ref_sub(list);
 197
 198         return 0;
 199
 200 err:
 201         ttm_eu_backoff_reservation_locked(list);
 202         spin_unlock(&glob->lru_lock);
 203         ttm_eu_list_ref_sub(list);
 204         return ret;
 205 }
 206 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
 207
 208 void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
 209 {
 210         struct ttm_validate_buffer *entry;
 211         struct ttm_buffer_object *bo;
 212         struct ttm_bo_global *glob;
 213         struct ttm_bo_device *bdev;
 214         struct ttm_bo_driver *driver;
 215
 216         if (list_empty(list))
 217                 return;
 218
 219         bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;
 220         bdev = bo->bdev;
 221         driver = bdev->driver;
 222         glob = bo->glob;
 223
 224         spin_lock(&glob->lru_lock);
 225         spin_lock(&bdev->fence_lock);
 226
 227         list_for_each_entry(entry, list, head) {
 228                 bo = entry->bo;
 229                 entry->old_sync_obj = bo->sync_obj;
 230                 bo->sync_obj = driver->sync_obj_ref(sync_obj);
 231                 ttm_bo_unreserve_locked(bo);
 232                 entry->reserved = false;
 233         }
 234         spin_unlock(&bdev->fence_lock);
 235         spin_unlock(&glob->lru_lock);
 236
 237         list_for_each_entry(entry, list, head) {
 238                 if (entry->old_sync_obj)
 239                         driver->sync_obj_unref(&entry->old_sync_obj);
 240         }
 241 }
 242 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);